Theoretical Emission Spectra of Atmospheres of Hot Rocky Super-Earths

Abstract

Motivated by recent detection of transiting high-density super-Earths, we explore the detectability of hot rocky super-Earths orbiting very close to their host stars. In the environment hot enough for their rocky surfaces to be molten, they would have the atmosphere composed of gas species from the magma oceans. In this study, we investigate the radiative properties of the atmosphere that is in the gas/melt equilibrium with the underlying magma ocean. Our equilibrium calculations yield Na, K, Fe, Si, SiO, O, and O${}_2$ as the major atmospheric species. We compile the radiative-absorption line data of those species available in literature, and calculate their absorption opacities in the wavelength region of 0.1--100~$\mu \mathrm{m}$. Using them, we integrate the thermal structure of the atmosphere. Then, we find that thermal inversion occurs in the atmosphere because of the UV absorption by SiO. In addition, we calculate the ratio of the planetary to stellar emission fluxes during secondary eclipse, and find prominent emission features induced by SiO at 4~$\mu \mathrm{m}$ detectable by Spitzer, and those at 10 and 100~$\mu \mathrm{m}$ detectable by near-future space telescopes.

15 pages, 12 figures, accepted for publication in ApJ

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• KEPLER's First Rocky Planet: Kepler-10b
• Detailed Models of super-Earths: How well can we infer bulk properties?
• Chemistry of Silicate Atmospheres of Evaporating Super-Earths
• Spitzer Transit and Secondary Eclipse Photometry of GJ 436b
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• A new class of Super-Earths formed from high-temperature condensates: HD219134 b, 55 Cnc e, WASP-47 e
• Inefficient volatile loss from the Moon-forming disk: reconciling the giant impact hypothesis and a wet Moon
• Laboratory spectra of hot molecules: data needs for hot super-Earth exoplanets
• Cloud formation in metal-rich atmospheres of hot super-Earths like 55 Cnc e and CoRot7b
• Low Albedo Surfaces of Lava Worlds
• Lightning climatology of exoplanets and brown dwarfs guided by Solar System data
• Average Albedos of Close-in Super-Earths and Neptunes from Statistical Analysis of Long Cadence Kepler Secondary Eclipse Data
• Gas Phase Chemistry of Cool Exoplanet Atmospheres: Insight from Laboratory Simulations